The disease is characterized by hardening of the brain tissues precipitated by the cyberization process.

As no cure officially exists, cyberbrain sclerosis is always fatal. Although the odds of symptoms manifesting are exceedingly low, anyone that has a cyberbrain is potentially at risk – and just about every productive member of society has one.

In 2019, at a time when cyberbrain implantation was just becoming common, a certain cyberbrain disorder of mysterious origins caused a stir in the medical field. Sections of the brain that received cyberbrain implants gradually hardened and eventually lead to brain death. The disorder was later named cyberbrain sclerosis. While the probability of getting this disorder was not high, anyone with cyberbrain implants was susceptible. Since no cure had been found, it was ranked along side tuberculosis, cancer, and HIV the incurable diseases of the 21st century. In terms of specific symptoms, slight memory loss is the disease’s preliminary warning sign. As the illness worsens, symptoms include deterioration of speaking ability, incompatibility with external memory storage units, and severe memory deficiency. Eventually, those afflicted will face brain death, or so it was thought. While it was possible to delay the symptoms’ progress with appropriate treatment, it was believed sclerosis itself could not be cured, causing a momentary yet considerable panic within the cyberbrain-implanted population when the disease’s existence was first disclosed to the public. As if they had entirely forgotten that they cheerfully advertised the advancement and application of cyberbrain technology in the past, various media began to indulge in their customary off-the-point and delayed criticism of high-ranking government officials who retired to posts in cyberbrain manufacturing companies.
Concurrently, the public jumped on the bandwagon, resulting in the creation of many anti-cybernetics organizations represented by groups such those belonging to the Human Liberation Front and those advocating the resurrection of return-to-nature movements.

The Murai Vaccine, which was developed by Dr. Murai Chitose, is an undeniable and highly effective treatment for cyberbrain sclerosis, though the mechanism by which it worked was never identified. However, medical experts at the time consisted largely of MicroMachine treatment advocates. The vaccine treatment developed by Dr. Murai was conceptually behind the times, and the majority felt that allowing his research would delay completion of the concurrent research on MicroMachine treatment, which held great promise as a highly versatile technology despite its early stages of development. Certain company and government officials believed that if the vaccine was released, it would hinder the development of micromachine technology. Perhaps because of such concerns, approval of the Murai vaccine was delayed. Dr Murai, who hoped for the approval of his vaccine treatment until the very end, died an unfulfilled death in February 2021 at age 68, without witnessing the decision of the drug evaluation committee. However, in April 2021, the Murai Vaccine was suddenly approved for special use by select individuals, after initially being rejected. This approval was not made public, and patients who used the vaccine do not officially exist.

Pressured by the public for a rapid response, the government announced a new treatment involving micromachines in order to pacify them. The publicized treatment did not have a significant effect, and many questions remained. However, the media dashed off to search for the next scandal after burying a few scapegoats, and the public forgot their problems with customary alacrity once the media dropped the subject matter. As a result of such routine work, the hysteria over anti-cybernetics movements consequently subsided. But the past of CS and the existence of Murai did not die in 2021. Even now, there are those who are interested in the situation.

Enter the Sunflower Society -a non-profit Organization that supports individuals who file suit against the government and large corporations. They demanded disclosure of information on the Murai vaccine and those who have received the vaccine from government agencies on multiple occasions in the past. However, the Ministry of Health, Labor, and Welfare used the Individual Privacy Act as a shield to reject their demands.